Height before and after 1 Tonne shackle installation
Like the majority of jobs on a Series Land Rover they can be technically simple but require a lot of logistics to acheive the 'technically' simple task. Supporting a 1.5 tonne Land Rover while hauling around the rear axle and spring assembly could lead to some horrific injuries if it is not attempted sensibly.
Pro's and Con's
To fit 1 tonne shackles to the rear of a SWB will give you the advantage of improved rear axle articulation and it will also (in the case of my SIII with parabolic fronts and standard rear springs) level out the whole vehicle. Approximate rise on new 11 leaf springs will be 2" (the length of the new shackle is only 1" longer than the original but the increased angle of around 30 Degrees generates the additional lift). The disadvantage is that the height increase gives an obvious (slight) increase in the amount of body roll (I would never by a Series LR for its handling anyway). But,in Cartman's case the offset was an improvement in rear suspension comfort - I don't know why?
NOTE:- I only refer to a rear 1 tonne shackle install. Front 1 tonne shackles can cause problems with the additional load on the UJ's on the front propshaft caused by the acute angle that they are forced to run at. Many people get away with it without any initial probs, but expect excessive wear.
Parts required :-
2 off Shackle plates (Part No.537778)
2 off Shackle plates (Part No.537734)
2 off shackle spacers (Part No.509218)
4 off shackle bolts and Nylok nuts (Part No.537741)
2 off spacer bolts and nuts (Part No.BH608361L)
1 tonne dampers (these have the necessary longer stroke) Or ProComp which are designed for longer articulation.
Standard axle straps can be retained if the securing points are dropped so that they are secured only on one bolt at each end of the strap. If you are using ProComp series dampers then no straps are required as they have internal stops. 1 tonne extended axle straps are available if you wish.
Extended bump stops are unnecessary.
Graphite grease or Coppaslip
Jack capable of lifting the rear crossmember 24"
Trolley jack to support the differential.
Something to safely support the rear cross-member at 24"
The Method....................
Park the LR on level and solid ground
Loosen nuts on both rear road wheels to aid wheel removal.
Chock the front wheels.
Remove the retaining nuts on each rear shackle. One on the chassis bush and one on the spring on each side.
Loosen the shackle bolts slightly.
Raise the rear crossmember up until the rear road wheels are approximately 2" above the floor.
Support the rear crossmember for safety.
Remove both rear road wheels.
Remove the rear axle strap on each side and relocate as necessary (see above) or remove (If dampers with an internal stop are to be fitted).
Remove rear dampers from their lower mount.
Support rear axle with a trolley jack under the differential.
Remove the shackle bolts and plates on either side so that each spring drops.
Lower the differential/axle assembly with the trolley jack so that an adequate distance is created between the spring and the chassis shackle mounting point in order to fit the new longer shackles. It may be necessary to slightly loosen the rear spring front shackles to allow the spring to pivot.
Starting with the LH spring install the new shackle plates with the spacer. Lubricate the upper & lower bolts well with graphite grease before installation, do not tighten the bolts yet. If the spring will not fall to give an adequate shackle insallation distance you will need to loosen the front shackle bolt. Check that the bolts are installed with the threaded plate and nuts to the centre of the vehicle.
Install the RH shackle as above.
Replace the both dampers onto their lower mounting points. Refit the check staps (if required) in their correct position to allow for the improved axle articulation and height.
Remove the trolley jack and refit the road wheels.
Lower the vehicle back onto all four wheels.
Tighten the road wheel nuts.
Rock the vehicle from side to side to allow the springs and shackles to settle into their original position then tighten all shackle bolts and nuts, both front and back of the rear spring.
You now have 1 tonne shackles!!!!
'1 Tonne shackles installed'
Updated 13 January 2003
me at pjboomer@freeuk.com